Lapping machine



i t 6 fire fi W 296162.34

April 27 1926. 1,582,207

J. N. BETHEL LAPPING MACHINE Filed July z. 1925 2 Sheets-Sheet 1 W fmY April 27 1926."

- J. N. BETHEL LAPPING MACHINE.

Filed July 2. 1925 2 Sheets-Sheet 2 Patented-Apr. 27, 19 26.

TENT OFFICE.

JOSEPH NJBETHEL, F WORCESTER, MASSACHUSETTS, ASBIGNOR '10 alarm-mam A COPARTNEBSHIP CONSISTING OF, J'OSEPH CO., OF WESTBORO, MASSACHUSETTS, N. IBETH EL AND SIDNEY PLAYER.

Larrmo uaomim.

Application filed m 2, 1923. Serial in. 648,819.

To all whom it may con/00m:

Be it known that LJosnrn N Bn'rHnL, a citizen of the United States, residing at Worcester, in the county of Worcester and State of Massachusetts, have. invented a new and useful Lapping Machine, of which the following is a specification.

This invention relates to; a machine particularly designed for lapping piston rings 19 or other similar fiat work.

It is the general object of my invention to provide a lapping machine which will move the work between the laps in a particular] effective manner, somewhat resem 15 bling tlie movement of the work in hand pp More specifically, it is an important ob ect of my invention to provide a machine in which the work receives an eccentric rotary motion and a simultaneous oscillating move-. ment. In the preferred form, the period of oscillation is not an exact factor of the period of rotation, so that the oscillations occurat rogressively different points in the period of rotation. A-further object of my invention is to provide means for adjusting the amount of eccentricity, independent of the extent of oscillation. My-invention further relates to arrangements and combinations of parts which will be hereinafter described and more particularly pointed out in the appended claims. A preferred form of my invention is shown in the drawings, in which- Fig. 1 is a sectional side elevation of present invention and is fully disclosed in my copending application, Ser. No. 616,474 led Feb. 2, 1923, to which reference is made for a more complete disclosure of this portion of the machine. 1 A shaft 14 is fixed in vertical sition in the base and forms a bearing or a rota able casting or member 15. This casting comprises upper and lower parts (Fig. 1) having inte al connecting portions 15 at each side 0 a central recess, as shown in section in Fig, 4. A worm gear 16 is fixed to the member 15 and is continuously rotated by a worm 17, on a shaft 18 supported in bearings 19 in the base 10 and driven by i a pulley 20.

A gear 21 is mounted in the opening between the upper and lower parts of the member 15-and is keyed to the fixed shaft' 14. A short vertical shaft 22 is mounted in I bearings in the member 15 arallel to the shaft 14 and is provided wit a pinion 23 meshing with the fixed gear 21. As the member 15 is revolved about the shaft 14, the pinion 23 isthus given a planetar motion, revolving about the center of the shaft 15 and also revolving at the same time about its own axis. A crank pin 24 (Fig.

2) is mounted the lower face of the pinion 23 and extends through .a slot in an, arm 25 secured to the lower end of a-"s'econd short vertical shaft 26 (Fi 1). mountedvin t 6. member 15 parallel to the shafts 14 and 22. A plate 27 is fixed to the upper'end of the shaft 26, and when The shaft 26'is also A portions of my improved lapping machine, in mid position preferably extends diametthe section bein taken subst the line 11 in i 2;

Fig. 1 is a detail side elevation showmg the support for the upper lap;

Fig. 2 is a sectional p the line 22 in Fig. 1; I

- Fig. 3 is a detail sectional elevation along the line 3--3 in Fig. 2, and U Fig. 4 is a detail sectional plan view taken along the line 44 in Fig. 1

Referring to the drawings, I have shown a lapping machine having a base or frame 10, a lower lap 11, and an upper lap 12 supported by an arm '10 (Fig. 1), mounted ona post 13 secured to the base 10. The manner of supporting and vertically adjustmg the upper lap 12 forms no part of my antially along rically across the axis of the shaft 14. The plate27 is provided with a guide way 28 or a sliding block 29, which is slotted to receive bolts 30 by which it may upper laps 11 and 12. referably supported upu per lap frilly debe adjusted an view taken along in any desired position on the plate 27.

(plate 33 between the nonto the frame 10, one of.

i placed in the tion of mfy improved lapping machine, the method 0 operation is as follows:

The piston rings or other flat work are work holding p ate 33 which rests upon the lower lap 11 and which is laterally positioned by the studs 31 in the sliding block 29. After the work-is thus positioned, the upper lap 12 is lowered to engage the work, and the belt is then shifted to rotate the pulleg 20, the shaft 18; and the worm 17 mounte thereon, by which means the worm gear 16 and rotatable member 15 are continuously rotated.

Such rotation swings the shaft 22 in a circular path about the axis of the shaft 14, and also rotates the shaft 22 upon its own axis,carrying the crank pin 24 with it. The crank pin 24 by its rotation oscillates the crank arm 25., the shaft 26, and the guide plate 27 fixed to the upper end thereof. The plate 27 and block 29 are oscillated between the extreme positions indicated by broken lines in Fig. 2, while at the same time the plate and block rotate with the member 15 and carry with them the work plate 33. The plate 33 thus receives an eccentric rotary movement through the studs 31 and is alsosimultaneously oscillated by the action of the crank 'n 24.

The teet of the gears 21 and 23 are preferably selected so that the teeth of the pinion do not constitute an even factor of the teeth of the gear and consequently the oscillating movements of the plate and block do not occur at fixed points in the rotation ofthe member 15 but change progressively with each revolution of the member.

The path of movement of a point in the work holding plate is indicated by the broken line B in Fig. 2, the point progressing in the direction of the arrow (1 in a somewhat irregular orbit and completing each revolution at a point slightly removed from its place of be nning. The path of movement. of the axis of the crank pin 24 for the same eriod is indicated by the broken line C on i 2. It thus appears that the work is move 1n asomewhat irregular path between the surfaces of the two fixed laps and that this movement is progressively advanced with relation to the laps so that the entire lapping surface of both upper and lower laps is engaged by the work as the lapping operation continues.

Asthe plate 27 oscillates it will attimes be moving in the same direction as the member 15, thus increasing the speed of the work relative to the fixed laps and at other times it will be moving in a direction opposed to the rotation of the member 15, thus reducing the relative speed to the difference between the two movements. In this way the rate of movement of the work between the laps is constantly varied through a considerable ockets or openings in therange, as is also the locus of movement between the laps. This combination of eccentric-rotary and oscillating movements has been found in practice to be extremely satisfactory and to produce an accurate lapped surface in a relatively short period of time.

Havingthus described myinvention and the advantages thereof, I do not wish to be limited to the details herein disclosed otherwise than as set forth in the claims but what I claim is:

1. A lapping machine having, in combination, upper and lower laps, a work holding plate positioned between said laps, and means to give said work holding plate a combined rotary and irregular transverse movement.

2. A lapping machine having, in combination, upper and lower laps, a work holding plate'positioned between said laps, means to rotate said plate, and means to give said plate a simultaneous movement substantially transverse to the path of rotation thereof.

3. A lapping machine having, in combination, upper and lower laps, a work holding plate positioned between said laps, means to rotate said plate, and means to give said of alignment with the axis of said plate, and means to oscillate said rotating plate.

5. A lapping machine having, in combination, upper and lower. laps, a work holding plate positioned between said laps, meansto rotate said plate, and means to give said plate a simultaneous movement substantially transverse to the path of rotation'thereof and to cause the transverse movements in successive rotations to occur at progressively different oints in the rotation of said plate.

6. A apping machine having, in combination, upper and lower laps, a work hold ng plate positioned between said laps, means to rotate said plate in an eccentric path, and means to oscillate said rotating plate and to cause the period of oscillation of said plate to be different from the period of rotation of said late.

7. A apping machine having, in combination, upper and lower laps, a work holding plate positioned between said laps, means to rotate said plate about an axis which is out of alignment with the axis of said plate, and means to oscillate said rotating plate and to cause the points of extreme oscillation" of said plate to occur at progressively different points in the rotation of said plate at successive revolutions thereof.

8. A-lapping machine having, in combination, upper and lower laps, a work holding plate positioned between said laps, a rotatable member, means to rotate said member,

rotate said plate about an axis which is out a fixed gear, a pinion on said member engaging said fixed gear, a crank pin rotated by said pinion, an arm mounted on said member and oscillated by said crank pin, and a connection from said arm to said work holding plate, whereby said plate isrotated eccentrioally' with respect to its axis and is also periodic-ally oscillated.

9. A lapping machine having, in combination, upper and lower laps, a work holding plate positioned between said laps, a rotatable member, means to rotate said member, a 'iixed gear, a pinion on said member engaging said fixed gear,a crank pin rotated by saidpinion, an arm mounted on said member and oscillated by said crank pin, a shaft hav ing a bearing in said member and on which said shaft, and a plate driving block slidable ahd adjustable on said plate.

10. A lapping machine having, in combination, upper and lower laps, a work holding plate positioned between said laps, means to rotate said plate about an axis which is out of alignment with the axis of said plate,

means to move said platebodily substan-' tially transversely to the path of rotation thereof, and means to simultaneously change the eccentricity of rotation and the range of transverse movement.

11. A lapping machine having, in co1nbination, upper and lower laps, a Work holder rotatably mounted between said laps, and means to move said holder back and forth transversely to position its axis alternately at opposite sides of the axis ol? one of said laps.

aflixed my signature.

JOSEPH N. BETHEL. 

